Gas lift device for pumping wells



Feb. 16, 1932. F. w. HARRIS GAS LIFT DEVICE FOR PUMPING WELLS v original Filed July 51, 1928 5 Sheets-Sheet l F. w. HARRIS GAS LIFT DEVICE Foa PUMPING WELLS Feb.-16, 1932.

5 Sheets-Sheet 2 Original Filed'July 5l, 1928 Feb. M, 1932. F. w. HARRIS 1,845,149

GAS LIFT DEVICE FOR PUMPING WELLSA Original Filed July 51, 1928 5 Sheets-Sheet 3 i; u u iff Feb. 16,- 1932. F. w. HARRIS GAS LIFT DEVICE FOR PUMPING-WELLS Original Filed July 5l, 1928 5 Sheets-Sheet 4 www 2 /rv VEA/Toe.'

Feb. 16, 1932. F. w. HARRIS a 1,845,149

GAS LIFT DEVICE FOR PUMPING WELLS Original Filed July 3l, 1928 5 Sheets-Sheet 5 Patented Feb. 16, 1932 unire FORD W. nARRIs, on Los ANGELES, CALIFORNIA GAS LIFTDEVICE FOR PUMPNG XVELLS Application filed. July 31, 1S28,-Seria1 YNo. 296,493. Renewed January `11, .1930.

My invention relates tothe art of pumping and particularly to liquid lifting devices in which gas is used as a motive means ior elevating a liquid. Devices of this general 5 character haveV been used for a long period, being generically known as air-lift pumps. Such devices were originally applied to the lit-ting of water from wells or mine 'shafts and i When so used employed compressedair as the G motive means. Oli late yearsthe principle of the air-lift has been employed in the pumping of oil Wells andrwhen so used it has been found expedient to employ natural gas as a motive means. Air being a mixture of gasesY lo the use of natural gas is merely a matter of safety and convenience, the method of operation and theory involved being exactly the same whether air or any other gas is used. My invention is adapted to ybe applied tothe pumping of oil, water, or other fluids using air or any other gas as a `motive means. To illustrate fully one Ymanner in which it may be employed I have, however, elected to show s and describe its application to the pumping of an oil well using natural gas as a motive means. Vlhile7 therefore in the following specification I shall describe this particular use, I do not wish to be understood as limiting myself to the pumping of oil from a well using J gas as a motive fluid since my invention may be readily adapted by one skilled in the art to pump any liquid from any location using any gas. Y

. Prior' arzt' in the 'form of bubbles which reduce the average specific gravity of the liquid and gas mixture thus formed to a suicient degreeto cause Lthe mixture to flowl outwardly from n the top or" the eduction pipeand to draw flowing upwardly through the eduction pipe liquid into the lower end of the eduction'pipe, Y due to the fluid head set up by the liquid in the well. 'The operation of such air-liftdevices is well understood Aand such devices are in general use for pumping both oil and 55 water, using either compressed'air or in some cases compressed v,natural gas.,y s f Such ldevices have certain fundamental'deiects which are Well recognized. For pur poses of comparison with my invention, Wil be suiiicient to enumerate four defects.` t The first defect, which is especiallyl apparent in the pumping of oil Wells with natural gas, arises from the intimate mixture of the gas bubbles with the oil whichforms an emulsion or foam fromwhich it is -diilicult to separate the gas after theemulsion is Vdelivered to the gas-trap into which the well commonly discharges. s f o g `l rlhe second Adefect arises from the same intimate admixture since this tendsto promote absorption yof*l gasolineV vapors inA the thus robbing the oil of one of its most valuable constituents. j

The third defect is the abnormallyhigh gas ypressures requiredto start and in some cases to maintain the flow of fluids in the eduction pipe. To start any suchgas-'liti in an oil well it is necessary to employ gas under a unit pressure higher than the unit pres- Vsure ofthe oil at the point of admission vof the gas, the unit oil pressure being established by the head of oil in the Well above this point. Since eliicient operation l[of the gas-lift requiresthat this headbe a considerable raction of the total lift,the submergence pressure may in thecasevof deep wells be very'high amountingto several thousand pounds Vper square inch. The production of gas pressures and the maintenance of pipe lines and com-y pression machinery employing these I high pressures is diiicult and expensive.

Where it is possible to get a `high p submer# genre, that is to say, Where the natural oil level in the well. stands s uiliciently highto maire the head of oil above the point of submergence equal to sixty percent ormore of yhe total length of eduction pipe used, gaslitts operate satisfactorily except 'orfthe de` feets above mentioned.

The fourth defect of the standard form of gas-lift arises from the necessity for a high degree of submergence, such lifts being impractical where it is desired to pump a well down to a low submergence. Since oil iiows into a well at a rate proportional to the difference between the natural fluid pressure in the oill bearing strata surrounding the well and the counter-pressure set up by the head of oil maintained in the well, it is obvious that to get maximum production from a well it is desirable to keep the level of the oil standing in the well as low as possible. This prevents the gas-lift from operating eiciently or in fact from operating at all if the submergence pressure is very low and the lift very high.

VTo obviate some of these defects various expedients have been adopted by various prior inventors. In some cases intermittently opera-ted deviecs are'used, which allow the eduction pipe to fill with oil for a certain period, gas Vthen beingall-owed to flow `for a further period, the oil flow then beingV shut 0E and the cycle repeated. A gravity operated foot valve is Vcommonly employed in the bottom of the eduction pipe belowthe point of gas admission, this valve closing as the ilow of gas starts and allowing the gas pressure to build up behind the oil, which is thus ejected in a more or less solid column. i Such vintermittent devices require a gas pressure slightly higher than the submergence pressure, that is, the unit pressure of the oil at the point of admission of gas, this pressure being, of course, directly proportional to the head of oil standing in the well above thispoint. In such devices the flow of gas practically empties the eduction pipe of oil and as the pressure falls therein, due to the shutting off of the gas supply by the intermittently operatedcontrol, the foot valve is opened by the excess of submergence pressur-e and the eduction pipe fills.

The device shown in the patent to Pendleton, No. 1,523,709, patented Jan. 20, 1925, is intended to correct certain defects in the operation of the intermittently operated devices just described. VIn the Pendleton device a foot valve is provided at the lower end of the eduction pipe, this foot valve lifting under the influence of the submergence pressure and allowing the eduction pipe to lill up to the level of the oil in the well. As soon as the eduction pipe is filled, the foot valve falls, due to its own weight, and as it seats, it shuts ott' further'flow of oil into the well. A gas valvethen opens, allowing gas at a pressin'e slightly higher than the submergen-ce pressure to enter the eduction pipe and expel the o1l by forcing it upwardly through the eduction pipe. As soon as the oil is expelled, the pressure in the eduction pipe falls by a certain amount below the submerg-ence pressure and the foot valve rises, shutting oli the gas supply and opening the oil supply, thus allowing the eduction pipe to again lill.

The Pendleton device automatically iills the eduction pipe with oil to the fluid level and then ejects the oil and repeats the cycle. :d

Objects md advantages (a) It is an object of my invention to provide a d-evice using gas as a motive means which will be free from the defects and objections found in prior devices of this character.

(b) It is a'further object of my invention to provide such a device which is so constructed that there will be no substantial emulsiiication of the gas with the iluid to be pumped.

(c) It is a further object of my invention to provide a device which is adapted to pump oil using gas as a motive means in such a manner that there will be a low absorption of the more volatile fractions of said oil by the gas. Y y

(d) It is a further object of my invention to provide a device in which gas of a much lower pressure may be used as a motive means than has heretofore been considered possible.

(e) It is a further object of my invention to provide a pump utilizing gas as a motive means in which the fluid is pumped with gas at a pressure very materially lower than the subinergence pressure at th-e point of gas admission.

(f) It is a further object of my invention to provide a pump using gas as a motive means in which I fill the lower end of the eduction pipe` or fluid delivery tubing) with a charge ofoil which establishes a pressure (at the point of gas delivery) slightly below the operating pressure of. the gas regardless of what this pressure may be at that time.

Further objects and advantages will b-e made evident hereinafter or will be apparent to one skilled in the art from an understanding of the disclosures made herein.

Descr/piana of ygures Fig. 1 is a somewhat diagrammatic elevation (partly in section) of apparatus adapted to practice my invention.

Fig. 2 is a section through the upper portion of the valve structurerused by me in the manner shown in Fig. l.

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Fig. 3 is a section through the low-er portion oi' said valve struct-ure, Figs. 2 and 3, taken together, illustrating one form of thisk structure.

Fig. 4 is a section on the line 4--4 of Fig.f

8 is a diagram showing the valve f means with the parts in what may be termedA the first position with oil flowing into tl from the gas supply pipe shut oit".

Fig. 9 is a similar di( gram showing the parts in what may be termed the third or iinal position.

Fig. l() is a similar diagram showing the parts in what may be 'termed an intermediate or second position they pass towards (or away) from the iinal or third position.

Fig. 1l is a pressure diagram showing.` the pressures on various parts oi the apparatus at various positions.

Fig. l2 is a section through the upper portion of the apparatus shown in Fig. 2 as modified to permit the use o'f' a packer and the omission of the supply pipe, the casing forming in this case the gas supply line.

GENERAL BnscRIrTroN Installa-tica as a 'whole Referring to F l. 2O is the casing of the well, which extends above the surface of the ground shown at 2l-2l and down into the oil producing zone shown between `lines 22-22 and 22-22. rl`he easing is perforated at 23 to allow oil to enter the well which itwould naturally lill to a level 244-24 it allowed to stand undisturbed for a sutil-cient period. The level 24-24 naturally falls during the pumping operation. The casing 'is furnished with a casing-head 25, which supports a gas supply line 26, which is provid d with a fitting 27. '.lhe lit-ting 27 has an opening at one side to receive a pipe 28 and supports the iluid delivery (or oil) tubing 29, which is connected through an elbow with a pipe 30 having valve 3l through which oil and gas are discharged to a gas trap (not shown) in which the may be separated from the oil and reused if desired.. rlhe pipe 28 is provided with valve 32 and is connected to the pressure side of a compressor33 in which the gas is raised to a suitableipressure. Low pressure gas is taken into the compressor through a pi pe 34.

is a section on the line '-T of Fig. 3,-

il@ v3, fluid delivery tubing and with all flow oi gas i ln the normal operation oiy my invention, gas is forced downwardly kthrough the space between the tubing 29 and thegas supply` pipe 26 and oil and gas are delivered upwardly through the tubing 29. In some cases, by the use oi the structure shown in Fig. 12, l prei-er to omit the gas supply pipe 26 and use the casing 2l as ay gas supply pipe.

Val/ve means In Figs.y 2 to 7 inclusive I show valve means which are carried on the bottom of the tubing`29 and gas supply pipe r26. These means will now be described.

Reverse?" f For convenience I prefer to place the oil tubing or iuid delivery pipe inside the gas supply pipe, as shown, although the position of these Vpipes may be reversed. W hen using the oil tubing inside the gas supply pipe itis desirable to use reversing casting 40 to which the gas supply pipe 26 is secured by a threaded collar 4l and to which the oil tubing is secured by a threaded collar 42, as shown in Fig. 2. Threaded into the bottom of the reversing casting 40 is a valve shell 43 and secured by a threaded collar to the bottom of the casting 40 is an outer shell 44.

Ports provide open communication from the gas space between the tubing 29 and gas supply pipe 26 to a central cavity 46, wl ich is in open communication at all times with the space inside the valve shell 43, so that this space is at all times at substantially the pressure carried in the gas supply pipe. Ports 47 provide an open communication between the space inside the lower eni of the oil tubing 29 and the space inside the outer shell 44,. so that this space is always at' substantially the same pressure as the lower end oi the tubing and is hereinafter lsometimes called the oil chamber. The purpose ot the reverser is to place the oil pressure in the space between the vshells 43 and 44 and the gas pressure inside said shell 43.

Gas calce, check voaf/Zee amd equaliser Secured by a threaded collar 48 to the bottom of the Valve shell 43 lisa valve housing 50. This is provided with a central cylindrical valve cavity 5l having a check valve port 52 at its upper end communicating with rthe gas space inside the valve shell 43. This port is normally'closed by a spring operated check valve 53, which functions to allow gas to i'iow readily from the gas space into the valve cavity 5l, but prevents areverse tflow. Ports 54 allow gas to flow readily from the space around the valve 53 into the chamber 51. Y 1

Formed in the walls oi the valve cavityil are gas inlet ports 55, which connect the cavity 51 with the gas space outside the yvalve t shell '50. Sliding `freelyin (but making a 'l substantially gas-tight closure with walls of) the valve cavity 5l is a gas valve plungerr56.

VThis plunger has a reduced portion 5'? so that with the plunger in its lower or third position as shown in Fig. 2 and F ig. 9, gas may flow downwardly around the reduced portion 57 and outwardly into the oil chamber surrounded by the outer shell 44. The head 58 of the plunger-56 also fits tiOht-ly in the valve cavity 5l and in its lower or third position, as shown in Figs. 2 and 9, it closes all communication between the upper part of the valve cavity above the head 58 andl the rest of the apparatus except through the port 52, which is normally closed by the check valve 53, as previously explained.

The head 58 and portion 57 of the plunger 56 are also of such proportions that with the plunger in its upper or first position (as shown in Fig. 8), the ports 55 are in open communication with the cavity 5l above the head 58, thus insuring that at the beginning of the lifting action the pressures are equalized, as hereinafter explained.

Foot or oz'Z valve Secured to the outer shell 44 by a threaded collar 59, as shown in Fig. 3, is a foot valve casting 60. Also secured to the foot valve casting 60 by a collar 6l is a piston cylinder 62. A central cylindrical foot valve cavity 63 is provided in the foot valve casting 60 and an oil valve plunger 64 slides therein forming a gas-tight closure with the walls thereof. Oil inlet ports 65 are provided in the walls of the cavity 63 through which oil may ent-er from the space outside the casting 60, which is immersed in the oil in the well. Ports 66 are also provided between the cavity 63 and the oil space inside the outer shell 44. The oil valve plunO'er 64 is provided with a portion 67 of reduced diameter, which is so situated that with the plunger in its rlower (or third) position, as shown in Fig.

9, all communication between the ports and 66 is cut off and no inward flow of oil can occur, but as the plunger rises to its upper (or first) position, as shown in Fig. 8, communication is established between these ports and oil flows freely from the well into the oil space inside the outer shell 44.

@pointing piston `Sliding freely in the piston cylinder 62 (but forming a gas-tight joint with the walls thereof), as shown in Fig. 3, is an operating piston 70. rlhe upper surface of this piston is at all times open to tubing pressure for pressure in the oil space inside the outer shell 44), since the cylinder 62 does not connect with the valve housing 50 and a space is left therebetween. The gas valve plunger 56 is preferably integral with the piston 70, as is also the oil valve plunger 64, tl e piston and two plungers operating as a single unit. A

central opening 71 is provided through the Vplungers 64 and 56 and the piston 70, so

that the space directly above the plunger 56 and the space directly below the plunger 64 are at all times in open communication with each other. Ports 72 are also so formed in the plunger 64 and so placed that a gas storage reservoir 3 formed inside the cylinder 62 below the piston 70 is at all times in communication with the upper part of the gas valve cavity 51. A compression spring 74 may be utilized to force the piston T0 downwardly, although the weight of the piston and plungers 56 and 64 may be sufficient.

Mmnon or OPERATION Y Installation and starting The part-s shown in Figs. 2 and 3 being assembled as shown in those figures, the device is lowered into the well (by adding joints of oil tubing 29 and gas supply pipe 26 to the top of the strings of pipe until the desired depth is reached), and the apparatus is connected as shown in Fig. 1. lVith the parts in the third or lower position, as shown in Fig. 2 (and Fig. 9) the oil valve is closed (no flow being possible through the ports 65 and 66) and the gas valve is open, `gas being free to iiow through the ports 55 into the oil chamber.

if with the parts in the position shown in Fig. 9, the lower (or third) position, the valve l is closed and the valve 32 is opened, gas pressure is built up, first in the gas supply pipe 26 and then in the oil tubing 29, the pressure equalizing therebetween through the ports 55.

During the time the pressure is building up in the gas supply pipe 26 and the oil tubing 29 the pressures on both sides of the piston 70 are eq ual, gas entering the cavity 5l by lifting the valve 53 from its seat and flowing downwardly through the opening 7l and the ports 72 into the storage reservoir 73. The same pressure acts on the upper surface of the piston, since the same gas pressure is established above the oil chamber through the ports 55. The piston 70 therefore remains in its lower (or third) position, as shown in F ig. 9.

When'the pressure inside the system has built up to the maximum which the compresser 33 will produce, the valve 3l is opened and gas blows violently out of the pipe 3() and the pressure in the gas supply pipe 26 and the tubing 29 rapidly falls. l

The pressure in the gas storage reservoir 3 does not fall since the valve 53 seats and holds the gas storage reservoir 73 under the maximum pressure previously established, communication with lthe ports-55 being shut olf by the head 58 of the gas plunger 56. As soon as the pressure in the gas storage reservoir 3 exceeds the pressure in the oil chamber above the piston 70 by an amount sufficient to overcome the weight of the piston 7 0 (andl its attached plungers) and the pressure of the spring 74, the piston 70 is forced upwardly, through the second position shown in Fig. l() and to thefirst position shown in Fig. S. Tn this position3 the'gas valve is closed.l i. e. the ports 55 can no longer discharge into the oil chamber and the gas pressure in this chamber and in the tubing 29 rapidly lowers town.A ls atmospheric'pressure (due to the rapid escape of gas through the pipe 30). This increases the pressure tending to hold the piston up, since the gas reservoir 'Z3 is in open communication through the ports 72, the opening` Il, and the ports with the gas pressure in the ,uns supply pipe 26. The device is now inposition to be filled with oil.

F lling `With the parts in the first position, as

shown in Fig. 8, the oil valve is open and oil readily flows through the ports and 66 into .fthek oil space inside the outer shell 44- and upwardly therethrough and through the ports 47 into the oil tubing 29. The valve 31 being` open, the gas pressure previously in the oil tubing 29' rapidly falls to a low pressure (due to escape of gas through the pipe)l before the oil filling operation is com-,-

pleted.

Oil is forced into the oil tubing 29 throughy the ports 65 and 66 due to the submergence head. Tn starting the pump this head may be considerable, amounting in some cases to one thousand pounds per square inch. The

submergence pressure Vfalls as theU 'wellv pumps down or the fluid in the well is pumped out. It is an object of my invention to allow the well to be pumped with a small gas pressure, which maybe as low as one hundred pounds per square inch.

During the filling voperation the piston 7 0 lis held up by the gas pr-essure of say one.

hundred pounds per square inch. .As the tubing 29 fills with oil through the oil chamber in the shell 44, this oil exerts a downward pressure on the top of the piston 70, this pressure gradually increasing. Q y

vWhenever the oil pressure on the top of the piston aided by the weight of the piston (and its attached plungers) and the force of the spring 7 4 exceeds the pressure on the bottom of the piston7 the piston moves down.

This may Occui when kthe oil pressure is sayV eighty pounds per square inch, the necessary remaining downward forcebeing supplied by the weight of the piston (and its attached Y `plungers) and the spring 74. The piston 7U having moved down through the second position into the third position the lifting opera tion starts.

Lifting `Wi=th the parts in the .third position, as

sure of vsay one hund-red pounds per square" inch andis therefore in excessof the oilpresl sure of eighty pounds per square inch, so that it lifts the oil in the tubing. 4 The columnl ofoil in the tubing is something over two hundred feet long and this piston of oil is lifted by the pressure. applied to itslower surface rather than by the infiltration of gas bubbles as in the ordinary gas-lift.v Some mixing of oil and gas occurs, but the gasbubbles `so produced are relatively large and the oil moves upward substantially in-y a solid massj and is forced out throughthe valve 31 andthe pipe 30 into the gas trap (not shown). n y

vDuring this upward movement .of tlieoil` the gas pressure raising it falls very little, since the head of oillifted remains constant at eighty pounds pressure and-friction lossesand power needed to `accelerate the oi-l ree quire a considerable .excess` of pressure to-n lre'ep it moving. n v

As soon as the oil starts to leave the pipe 30Y the pressure required to lift the oil' rapidlyy falls. Itvwill be noted that astlie piston 7G" wasr forced downwardly the head 58 there-l of closed the communication between the'l chamber .51 and the ports 55 before either the` gas valve opened or the oil kvalve closed vand as at the maximum pressure of one "huur- C red pounds per square inch was trapped/in the gas storage reservoir. During lthe entire lifting operation the vpiston 770- is thereforeacted upon by the maximum pressureof one, hundred poundsper` square inch; As

therefore as the pressure on top of the pistonl falls below ,eighty `pounds per square inch the piston is forced upwardly intov the-A first position. This diminution in pressurel off. The gas in the tubing 29 below the oil continues to act expansively,'howeverfandY the oil flow continues until all tl-ieoillea-ves the pipe 30. The gas in the tubing 29 then flowsvery rapidly therefrom and the pressure in thetubi-ng rapidly :approaches atmospheric during which the tubing refillsAv asi already explained and the cycle repeats ittion it is desirabl'eto providek a pressure regulating valve 8O and a pressure gauge 81 in the gas p'ipe'28. Y' i w It will be found expedient to start with' 'a' relatively high press-urer in the gas supply' pipe 26 and to lower this pressure as the welf In the practical operation-of invenf any value may be used which is so constructopen communication with through the ports 72 andthe opening 71 so 'check valve 53 and 'in Fig. `8, the tubing flowing ed that it opens when the pressure in the gas supply pipe 26 falls below the pressure for which the valve 8O is set and closes when the pressure in the pipe 26 rises to a point just below the pressure for which the valve 8O is set.

Equalization An important but not absolutely essential y feature of my invention is the equalization of pressure between the gas pressure reservoir 78 and the source of gas supply whenever the device assumes the first position as shown in Fig. 8. In this position, the head 58 of thel plunger 56 is wholly within the cavity 51, `which is therefore in open communication with the ports through the space around the reduced portion 57 of the plunger.

The gas in the gas reservoir space 73 is in the cavity 51 that at the instant the piston 7 0 starts down from the iirst position the gas in the gas reservoir space is at the pressure existing in the gas supply pipe 26 at that time. This allows the pressure in the space 73 to adjust itself to suit changes in the amount of pressure in the gas supply lpipe 26, which may occur through changes in the source of `gas sup- Y ply due to accident or to adjustment of the valve 80. Y

'It will be noted that the ports 72 are so placed that they open into the lower part of the gas reservoir space at all times. This is for the purpose of pumping oil out of this 'space should any leakage of oil occur into this space. Suppose for example that in starting the pump with the parts in the third position, as shown in Fig. 9, suiiicient oil has leaked into the gas reservoir 73 to fill it half full. This is an extreme condition which should never occur in practice, but will serve toillustrate the way oil is pumped out of this space. Gas pressure is established in the gas supply pipe '26 and this pressure opens the through the cavity 51, the opening 71 and the ports 72 bubbling up through the oil in the oil in the gas reservoir space'7 3.

When the pressure is released by opening the valve 31 the piston rises, and whenever the piston assumes the rst position, as shown pressure is at a low value and the gas inthe forcing the oil out through the ports 72 and the opening 71 into the cavity 51, this oil down and through the ports 55, until gas under pressure flowsV reservoir 7 3 expands,-

the pressure again rises in the gas supply pipe. A small amount of the oil ejected then remains in the lower part of the cavity 51 and in the open space surrounding the plunger 56 even though the gas pressure then again rises to a maximum and gas bubbles through this oil and back through the opening 71 and ports 72 into the gas storage reservoir 73.

The oil remaining in the lower part of the valve cavity 51 is then spilled down into tho oil chamber below the valve casing 50 (when the piston assumes the third position). This operation of forcing a little oil out of the gas reservoir 7 3 is repeated on each cycle ot operations and is suicient to more than compensate for any leakage thereto. In practice I prefer to make the length of the gas reservoir considerably greater in proportion than is shown in the diagrams, Figs. 8, 9 and 10.

Packer In some cases it may be desirable to omit the use of a separate gas supply pipe 26, which can be done by the use of a packer, as shown in Fig. 12. Packers are well known in the oil industry and many forms of such devices have been patented and are in general use. They are ordinarily used to make a gas-tight closure between the outside of a string of pipe (as for example oil tubing) and the inside of another string of as for example the casing of the well).

In the form illustrated in Fig. 12 I employ a rubber sleeve 90, which is placed over a sleeve 91 and compressed, against a shoulder 93 formed thereon, by a nut 92 threaded in the sleeve 91. The parts being assembled by suitable tools (not shown) as in Fig. 12, the sleeve 96 makes a gas-tight joint with the interior of the casing 20 above the perforations 23. The nut 92 is provided with a conical seat 94 on which a seat member 95 can rest in gas-tight relationship. The seat member 95 has threaded therein a short length of pipe 96 which is secured by a collar 97 to the reverser casting 40 previously described. The oil tubing or fluid delivery pipe 29 is also secured to this casing 40 in the same manner, as shown in Fig. 2, and the reverser casting 40 and all parts below this casting are exactly like those shown in Fig. 2 and previously described.

With the apparatus shown in Fig. 12 gas pressure is supplied through the space between the casing 2O and the oil tubing 29 and the gas supply pipe 26-may be omitted. Obviously other forms of packer well known in the art may be employed.

Pressure diagram pipev For example, at the time represented by the line 100-100 the pressure on the top of the piston 70 is falling along the line 101 and the piston 70 is in the third position, as shown in Fig. 9. The pressure on the bottom of the piston is sufficient to drive it up and the gas valve closes at 103, the oil valve opens at 104,

and equalization of pressure between the gas p supply pipe 26 and the gas storage reservoir takes place at 105. The pressure on the bottom of the piston 7 0 is represented by the line 102. This pressure falls slightly between the time the gas valve closes and equali- Zation starts as shown atlO? due to the eX- pansion of the gas in the gas reservoir 73 as the piston lifts7 and it falls sharply, as shown at 106, to the pressure of the gassupply pipe 26, which is about the same as the pressure on the bottom of the piston when equalization occurs 'as the gas valve closes at 103'.

The pressure on the bottom ef the piston then rises as shown at 108 due to a building up of pressure in the gas supply'pipe 26, which builds up the gas pressurein the reservoir by flowing around the head 58, the parts now being in the first position, as shown in Fig. 8. From the point 103 the pressure on the top of the piston rapidly falls as shown at 109 due to the rapid expansion of gas in the oil tubing 29. VDuring t ie period` 109 oil and gas are being rapidly expelled from the tubing 29 and the pressure falls on this aitcount. Y f

At the same `tilneoil is sing admit-tet through the ports and 66 and before the pressure on the top of the piston falls to zero considerable oil enters the tubing gradually building up the pressure due to this oil as the gas pressure in the tubing diminishes. The increase. along the line 110 represents this difference in pressure which continues until the oil pressure attains the value shown at 111 rwhen the piston is forced down, closing the equalizer' ports at 112, and the oil ports at 113 and opening the gas port 55 at 114-. During this time the gas supply pipe pressure remains at its maximum value, as shown at 115. There is therefore a sharp ise in pressureon top of the piston as shown at 11G when the gas port- 55 opens as the pressure on the top of the piston rises at this time to sub-y stantially maximum value, as shown at 11'?.

The piston is then in its lower or third position, as shown in Fig. 9, and full maximum oil pressure is applied to lift the oil until oil starts to leave the tubing through `the pipe 30. This occurs at 118 and the pressure on top of the piston starts to fall along the line 119 until it reaches the point 1031 when the valve. starts to lift and the cycle is repeated, the point 1031 corresponding to the initial point 103.

During the cycle the pressures on the piston follow the line 120v which represents the difference in gas pressure on the top and bot Vifhilel have stated that a pressure of one hundred pounds per square inch may be used'.

to jump a well hearingV an initial subinergence pressure ofa thousand pounds per square inchit is desirable to use higher gas pressures mitially and to reduce these `pressures as the well pumps down since operating with high submergence and low gas pressure is un-eco-V nomical. An important feature of inyinvenvtion is, however, that it may be operated withv a pressure considerablyless than the subinergence pressure, even instarting, and that the pump always takes in a little less oil thanA it can lift;

Having taken in a charge of oil the amount of which is determined by the available gas pressure and not dependent upon the submergence -pressure (or head of oil standing in the well) the device continues to operate until the well is pumped down to such a degree that the oil submergence pressure is less than the gas pressure used by an amount equal'to the downward pressure exerted by the weight of the piston 70 and its attached plungers andv the pressure of the spring 74. The device then stops with the parts in the first position. In this position the supply of gas is out off and the device remains idle until suilieient oil flows into the Well to reestablish the submergence pressure and force the piston down.

In practice an operator can readily tell when the gas pressure is too high by the fact that the device operates at longA intervals, in which event he adjusts the valve to lower the gas pressure, which in turn allows the device to operate at a lower submergence pres-v sure. The lower the submergence maintained the greater the production from the well. n

As already explained, the device operates'r until the well is pumped down toy a point wherethe submergence pressure is insufficient to move the piston 70 down out of the first position shown in Fig. 8. Tf it is desired to pump the well vdown further the regulating valve 80 is adjusted to deliver a lower gas pressure to the gas supply pipe 26. This adjustment of the regulator 80 does not, of course, in any way alter the gas pressure already present in this pipe and the changein adjustment of the regulatorSO does not in itself start the device in operation. lf, however, (after the regulator 8O is adjusted) pressure is slowly lowered in the gas supply pipe 26 as by example slightly o iening a valve 150, connecting the interior of the gas supply pipe 26 with the open air, the pump will start whenever this pressure falls to the submergence pressure, since the pressure holding the piston in the first position, as shown in F .1g. is the pressure in the gas supply pipe As this ressure is lowered the pressure in 1 7 ,T the chamber 3 also falls since this chamber 1,' 73 is, in the iirst` position shown in Fig. 8, in

open communication with the gas supply pipe 26 through the ports e7-2, the opening 7l, and the ports 55. As the piston falls, this communication is cut oil and the pump starts operating again. As soon as the pump starts the valve 150 is closed and the well is pumped down to a lower head determined by the adjustment of the regulator 80. When the pump is operating this regulator 8O can be g adjusted either up or down, as previously explained.

The apparatus disclosed herein is the first gaslift device ever disclosed in which the amount of the charge of liquid taken into the device is regulated solely by the gas pressure used and is independent of the submergencc pressure. It is also the lirst device in which a body of gas at the initial maximum pressure is trapped and held to be used as a means to shut on" the flow of gas whenever the pressure at the bottom of the liquid delivery tubing falls below this maximum pressure.

claim as invention:

l. A method of raising liquids by gas pressure which comprises: establishing a liquid column in suitable liquid deliver i tubing; establishing in opposition to a permanently applied force a supply7 ot gas under a definite maximum pressure; admitting said gas under approximately said maximum pressure to the lower end of said tubing in sui'licient amounts to raise said liquid in said tubing, said admission occurring whenever the pressure on the liquid column at the point of admission, plus said permanently applied force, becomes sufficient to overcome said maximum gas pressure; shutting oit further flow of liquid from the well into said liquid column at approximately the time of said gas admission; shutting off the flow of gas into said column and reestablishing the flow of liquid thereto whenever the pressure at said point of admission, plus said force, become insufficient to overcome said maximum gas pressure; and repeating the cycle until the amount of liquid available talls so low that said liquid column cannot establish itself to the required height.

2. A.. pump for raising liquid from a well, or the like, comprising: liquid delivery tubing extending, from the point to which itis desired to raise the liquid, down into said well; a liquid inlet valve adapted to close a liquid inlet port through which liquid may liow into the lower end of said liquid delivery tubing when said liquid inlet valve is open; a gas supply pipe; means for delivering gas under pressure to said gas supply pipe; a

gas .supply valve adapted to close a gas supply port through which gas may flow from said gas supply pipe into the lower end' of said liquid delivery tubing when said gas supply valve is open; walls forming a gas storage reservoir in which gas may be stored at the maximum pressure attained by said gas in said gas supply pipe; means exerting a permanent closing force on said liquid inlet valve for closing said valve whenever the pressure in the lower end of saidluid delivery tubing, plus said force, overcomes the pressure of said' gas'in said gas reservoir; means operating against said force for closing Asaid supply valve whenever the pressure in the reservoir overcomes the pressure in the lower end of said liquid delivery tubing and said force; and means connecting said liquid inlet valve and said gas supply valve so that one is opened as the other is closed and vice versa.

3. A gas-litt device comprising: walls forming a chamber; liquid delivery tubing in open communication vat all times with said chamber; a storage reservoir; a pressure responsive means permanently exerting a force in a primary direction and movable in'said direction whenever the pressure in said chamber, plus said force, overcomes the pressure in said reservoir and actuated in a reverse or secondary direction whenever the pressure in said reservoir exceeds the pressure in said chamber and said force; a das supply pipe; means for delivery of gas under pressure to said gas supply pipe; a gas supply valve adapted to close a gas supply port through which gas may flow into said chamber when said gas supply valve is open; a liquid inlet valve adapted to close a liquid inlet port through which the liquid to be pumped may flow into said chamber when said liquid inlet valve is open; and means by which said primary movement of said pressure actuated device closes said liquid inlet valve and opens said gas supply valve and said reverse or secondary movementV of said pressure actuated device closes said gas supply valve and opens said liquid inlet valve.

4l. A valve mechanism for a gas-lift pump comprising: a gas supply pipe; liquid delivery tubing; walls forming a cylinder; a piston sliding in said cylinder, said cylinder bcing open at the top to any pressure existing in said liquid delivery tubing, the space below said piston forming a gas storage reservoir; means for establishing gas pressure in said reservoir equal to the maximum pressure in said gas supply pipe; a gas supply llO valve adapted to close a port through which gas may flow from said gas supply pipe into said liquid delivery tubing when said valve is open; a liquid inlet valve adapted' to close a liquid inlet port through which the liquid to be pumped may flow into said liquidv delivery tubing when said valve is open; and means by which an upward movement of said piston closes said gas supply valve and opens said liquid inlet valve and a downward movement of said piston opens said gas supply valve and closes said liquid inlet valve.

5. A valve mechanism for a gas-lift pump comprising: a gas supply pipe; liquid delivery tubing; walls forming a cylinder; a piston sliding in said cylinder, said cylinder being open at the top to any pressure existing in said liquid delivery tubing, the space below said piston forming a gas storage reservoir; a. check valve adapted to close a port and prevent gas romi'lowing from said gas storage reservoir into Vsaid gas sup-ply pipe while allowing gas to flow from said gas supply pipe into said gas storage reservoir whenever the pressure in said gas supply pipe exceeds the pressure in said gas storage reservoir; means for establishing gas pressure in said reservoir .equal to the maximum pressure in said gas supply pipe; a gas supply valve adapted to close a port through whichf gas may flow from said" gas supply pipe into said liquid delivery tubing when said valve is open; a liquid inlet valve adapted to close a liquid inlet port through which the liquid to be pumped may flow into said liquid delivery tubing when said valve is open; and means by which an upward movement of said piston closes said gas supply valve and opens said liquid inlet valve and a downward movement of said pistons opens said gas supply valve and closes said liquid inlet valve.

6. A gas-lift device comprising: walls forming a chamber; liquid delivery tubing in open communication at all times with said chamber; a gas storage reservoir; a pressure responsive means permanently exerting a Jforce in a primary direction and movable in said direction whenever the pressure in said chamber, plus said force, overcomes the pressure in said reservoir and actuated in a reverse or secondary direction whenever the pressure in said reservoir exceeds the pressure in said chamber and said force; a gas supply pipe; means for delivery of gas under pressure to said gas supply pipe; a gasv supply valve adapted to close a gas supply port through which gas may flow into said chamber when said gas supply valve is open; a liquid inlet valve adapted to close a liquid inlet port through which the liquid to be pumped may flow into said chamber when said liquid inlet valve is open; means by which said primary movement of said pressure actuated device closes said liquid inlet valve and opens said gas supply valve and said reverse or secondary movement of said pressure actuated device closes said gas supply valve and opens said liquid inlet valve; and means for equalizing the pressurerbetween said gas storage reservoir and said gas supply pipe whenever said gas supply valve is closed.

7 In a gas-lift device the combination of A liquid valve means for admitting a charge of fluid into said device slightly less in amount than the gas pressure employed can lift, said gas pressure adapted to be substantially less than the pressure forcing said liquid throughy said valve means; means for closing said means whenever said charge is complete; gas valve means; means for opening said gas valve means after said charge is complete and thus allowing the gas to lift the liquid; and means for closing said gas valve means and opening said liquid valve means as the lifting operation is completed, the cycle then repeating itself, the amount of charge admitted being readily varied by changing the pressure employed. y

8. In a gas-lift pump, the combination of: walls forming a chamber having an opening into a body of liquid in which the walls are immersed; a liquid valve adapted to close said opening; a gas supply pipe communicating with said chamber through a gas valve means for supplying gas under a fixed pressure to said gas supply pipe; an eduction pipe through which liquid may be Vforced Jfrom said chamber; and pressure responsive means adapted to open said liquid valve and closey said gas valve whenever the pressure in said chamber is less than said fixed pressure by a certain maximum value `and to close said liquid valve and open said gas valve when the pressure in said chamber increases to a value less than said fixed pressure by a certain minimum value.

9. The method of pumping a liquid from a well or the like which comprises.: submerging a closed chamber in said liquid in said well; establishing a gas pressure which is materially less than that ofthe liquid surrounding said chamber; admitting liquid from the well to said chamber until the pressure in said chamber is suiicient to close liquid valve means communicating with said chamber and materially less than said fixed pressure; and then admitting-said gas under said lixed pressure to said chamber to displace said liquid from said chamber through a suitable eduction P1Pe In testimony whereof, I have hereunto set my hand at Los Angeles, California, this 25th day of July, 1928.

FORD W. HARRIS. 

